Drivers: hv: vmbus: Rework use of DMA_BIT_MASK(64)

Using DMA_BIT_MASK(64) as an initializer for a global variable
causes problems with Clang 12.0.1. The compiler doesn't understand
that value 64 is excluded from the shift at compile time, resulting
in a build error.

While this is a compiler problem, avoid the issue by setting up
the dma_mask memory as part of struct hv_device, and initialize
it using dma_set_mask().

Reported-by: Nathan Chancellor <[email protected]>
Reported-by: Vitaly Chikunov <[email protected]>
Reported-by: Jakub Kicinski <[email protected]>
Fixes: 743b237 ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

Author: kelleymh

drivers/hv/vmbus_drv.c

@@ -2082,7 +2082,6 @@ struct hv_device *vmbus_device_create(const guid_t *type,
 	return child_device_obj;
 }
 
-static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
 /*
  * vmbus_device_register - Register the child device
  */
@@ -2123,8 +2122,9 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	}
 	hv_debug_add_dev_dir(child_device_obj);
 
-	child_device_obj->device.dma_mask = &vmbus_dma_mask;
 	child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
+	child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
+	dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
 	return 0;
 
 err_kset_unregister:

include/linux/hyperv.h

@@ -1262,6 +1262,7 @@ struct hv_device {
 	struct vmbus_channel *channel;
 	struct kset	     *channels_kset;
 	struct device_dma_parameters dma_parms;
+	u64 dma_mask;
 
 	/* place holder to keep track of the dir for hv device in debugfs */
 	struct dentry *debug_dir;